scholarly journals Liquid droplets of protein LAF1 provide a vehicle to regulate storage of the signaling protein K-Ras4B and its transport to the lipid membrane

2021 ◽  
Vol 23 (9) ◽  
pp. 5370-5375
Author(s):  
Lei Li ◽  
Marius Herzog ◽  
Simone Möbitz ◽  
Roland Winter
Keyword(s):  
Lipid Membrane ◽  
Signaling Proteins ◽  
Liquid Droplets ◽  
Signaling Protein ◽  
Granule Protein

We found that membrane-less protein condensates, such as of P-granule protein LAF1, are able to provide an additional vehicle to regulate storage and transport of membrane-associated signaling proteins such as K-Ras4B to the lipid membrane.

Signaling Proteins as Innovative Targets for Antineoplastic Therapy: Our Experience with the Signaling Protein C-myc

2001 ◽  
Vol 87 (6) ◽  
pp. 20-23 ◽  
Author(s):  
Guido Cimoli ◽  
Luca Bagnasco ◽  
Maria Pia Pescarolo ◽  
Carlo Avignolo ◽  
Antonella Melchiori ◽  
...  
Keyword(s):  
Antineoplastic Therapy ◽  
Protein C ◽  
Signaling Proteins ◽  
Signaling Protein

The effect of caffeine on skeletal muscle anabolic signaling and hypertrophy

2017 ◽  
Vol 42 (6) ◽  
pp. 621-629 ◽  
Author(s):  
Timothy M. Moore ◽  
Xavier M. Mortensen ◽  
Conrad K. Ashby ◽  
Alexander M. Harris ◽  
Karson J. Kump ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Growth ◽  
Mtor Signaling ◽  
Signaling Proteins ◽  
Signaling Protein ◽  
Before And After ◽  
Amp Activated Protein Kinase

Caffeine is a widely consumed stimulant with the potential to enhance physical performance through multiple mechanisms. However, recent in vitro findings have suggested that caffeine may block skeletal muscle anabolic signaling through AMP-activated protein kinase (AMPK)-mediated inhibition of mechanistic target of rapamycin (mTOR) signaling pathway. This could negatively affect protein synthesis and the capacity for muscle growth. The primary purpose of this study was to assess the effect of caffeine on in vivo AMPK and mTOR pathway signaling, protein synthesis, and muscle growth. In cultured C2C12 muscle cells, physiological levels of caffeine failed to impact mTOR activation or myoblast proliferation or differentiation. We found that caffeine administration to mice did not significantly enhance the phosphorylation of AMPK or inhibit signaling proteins downstream of mTOR (p70S6k, S6, or 4EBP1) or protein synthesis after a bout of electrically stimulated contractions. Skeletal muscle-specific knockout of LKB1, the primary AMPK activator in skeletal muscle, on the other hand, eliminated AMPK activation by contractions and enhanced S6k, S6, and 4EBP1 activation before and after contractions. In rats, the addition of caffeine did not affect plantaris hypertrophy induced by the tenotomy of the gastrocnemius and soleus muscles. In conclusion, caffeine administration does not impair skeletal muscle load-induced mTOR signaling, protein synthesis, or muscle hypertrophy.

Novel and nondetected human signaling protein polymorphisms

2002 ◽  
Vol 10 (3) ◽  
pp. 159-168 ◽  
Author(s):  
Roy A. Lynch ◽  
Lynne Wagoner ◽  
Shunan Li ◽  
Li Sparks ◽  
Jeffery Molkentin ◽  
...  
Keyword(s):  
Genomic Dna ◽  
Evolutionary Conservation ◽  
Nonsynonymous Snps ◽  
Signaling Proteins ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Signaling Protein ◽  
Downstream Signaling ◽  
Small G Protein ◽  
High Degree

The frequency of single nucleotide polymorphisms (SNPs) in downstream signaling proteins was determined by combination heteroduplex HPLC and double-stranded sequencing of genomic DNA from 96–144 congestive heart failure (CHF) patients. Analysis of 56 coding exons in 9 signaling genes revealed 17 novel and 8 previously reported synonymous (no change in amino acid) SNPs, as well as one novel nonsynonymous SNP in the Rad small G protein. Because this initial analysis failed to detect numerous SNPs reported in the NCBI and Celera databases, double-strand sequencing of relevant exons from 74–91 CHF patients was used to confirm the absence of 10 previously reported nonsynonymous SNPs. Our results show that synonymous SNPs are frequent in signaling protein genes, whereas nonsynonymous SNPs are rare, suggesting a high degree of evolutionary conservation among these downstream signaling molecules. Comparisons of our results to the NCBI and Celera databases indicates that 56% of their SNP entries are not detected in our cohort. Importantly, while 31% of database SNPs were verified, 69% of SNPs detected in our cohort are not included in these databases. These findings indicate that caution may be warranted in relying exclusively on SNP databases as catalogs for polymorphic signaling protein genes.

scholarly journals Bardet-Biedl Syndrome 3 protein promotes ciliary exit of the signaling protein phospholipase D via the BBSome

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Yan-Xia Liu ◽  
Bin Xue ◽  
Wei-Yue Sun ◽  
Jenna L Wingfield ◽  
Jun Sun ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Phospholipase D ◽  
Basal Body ◽  
Regulatory Mechanism ◽  
Intraflagellar Transport ◽  
Bound State ◽  
Signaling Proteins ◽  
Bardet Biedl Syndrome ◽  
Signaling Protein ◽  
Ciliary Signaling

Certain ciliary signaling proteins couple with the BBSome, a conserved complex of Bardet-Biedl syndrome (BBS) proteins, to load onto retrograde intraflagellar transport (IFT) trains for their removal out of cilia in Chlamydomonas reinhardtii. Here, we show that loss of the Arf-like 6 (ARL6) GTPase BBS3 causes the signaling protein phospholipase D (PLD) to accumulate in cilia. Upon targeting to the basal body, BBSomes enter and cycle through cilia via IFT, while BBS3 in a GTP-bound state separates from BBSomes, associates with the membrane, and translocates from the basal body to cilia by diffusion. Upon arriving at the ciliary tip, GTP-bound BBS3 binds and recruits BBSomes to the ciliary membrane for interacting with PLD, thus making the PLD-laden BBSomes available to load onto retrograde IFT trains for ciliary exit. Therefore, BBS3 promotes PLD exit from cilia via the BBSome providing a regulatory mechanism for ciliary signaling protein removal out of cilia.

AEM analysis of solidification catalysts in atomized Fe-Ni

1986 ◽  
Vol 44 ◽  
pp. 584-585
Author(s):  
Matthew R. Libera
Keyword(s):  
Powder Particle ◽  
Alloy Composition ◽  
Particle Diameter ◽  
Metastable Phases ◽  
Liquid Droplets ◽  
Nucleation Kinetics ◽  
Ni Alloys ◽  
Nonequilibrium Solidification

The liquid droplets produced by atomization processes are believed to undergo substantial supercooling during solidification, because the catalytic heterogeneities, for statistical reasons, tend to be isolated in the larger droplets. This supercooling can lead to the nucleation of metastable phases. As part of a study on the effect of liquid supercooling on nonequilibrium solidification, three binary Fe-Ni alloys have been produced by conventional argon atomization (Fe-20Ni, Fe-30Ni, and Fe-40Ni). The primary variables in these experiments are: i) the alloy composition; and ii) the powder particle diameter (inversely proportional to supercooling). Of particular interest in this system is the competitive nucleation kinetics between the stable fee and metastable bec phases. Bcc is expected to nucleate preferentially with decreasing %Ni and decreasing particle diameter.

HREM observation of NiO growth on submicron spheres of pure nickel

1989 ◽  
Vol 47 ◽  
pp. 548-549
Author(s):  
C.M. Teng ◽  
T.F. Kelly ◽  
J.P. Zhang ◽  
H.M. Lin ◽  
Y.W. Kim
Keyword(s):  
Nickel Oxide ◽  
Grain Boundaries ◽  
Pure Nickel ◽  
Submicron Particles ◽  
Crystal Formation ◽  
Nickel Wire ◽  
Liquid Droplets ◽  
Oxide Interface ◽  
Nickel Chromium ◽  
Chromium Alloys

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.

Chapter 2b: The molecular antigenic structure of the TBEV

2020 ◽  
Keyword(s):  
Conformational Changes ◽  
Neutralizing Antibodies ◽  
Lipid Membrane ◽  
Cell Entry ◽  
Antigenic Structure ◽  
E Proteins ◽  
Amino Acid Sequence Level ◽  
Endosomal Membrane ◽  
E Protein ◽  
Golgi Network

TBEV-particles are assembled in an immature, noninfectious form in the endoplasmic reticulum by the envelopment of the viral core (containing the viral RNA) by a lipid membrane associated with two viral proteins, prM and E. Immature particles are transported through the cellular exocytic pathway and conformational changes induced by acidic pH in the trans-Golgi network allow the proteolytic cleavage of prM by furin, a cellular protease, resulting in the release of mature and infectious TBE-virions. The E protein controls cell entry by mediating attachment to as yet ill-defined receptors as well as by low-pH-triggered fusion of the viral and endosomal membrane after uptake by receptor-mediated endocytosis. Because of its key functions in cell entry, the E protein is the primary target of virus neutralizing antibodies, which inhibit these functions by different mechanisms. Although all flavivirus E proteins have a similar overall structure, divergence at the amino acid sequence level is up to 60 percent (e.g. between TBE and dengue viruses), and therefore cross-neutralization as well as (some degree of) cross-protection are limited to relatively closely related flaviviruses, such as those constituting the tick-borne encephalitis serocomplex.

Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter
Keyword(s):  
Outer Membrane ◽  
Lipid Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Membrane Channels ◽  
Gram Negative ◽  
Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

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